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 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
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 * file and include the License file at packager/legal/LICENSE.txt.
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 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
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 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
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package com.sun.mail.iap;

import java.io.*;

import javax.mail.event.ReadListener;

import com.sun.mail.iap.ByteArray;
import com.sun.mail.util.ASCIIUtility;

/**
 * 
 * Inputstream that is used to read a Response.
 * 
 * @author Arun Krishnan
 * @author Bill Shannon
 */

public class ResponseInputStream {

	private static final int minIncrement = 256;
	private static final int maxIncrement = 256 * 1024;
	private static final int incrementSlop = 16;

	// where we read from
	private BufferedInputStream bin;

	private ReadListener listener;

	/**
	 * Constructor.
	 */
	public ResponseInputStream(InputStream in, ReadListener l) {
		bin = new BufferedInputStream(in, 2 * 1024);
		listener = l;
	}

	/**
	 * Read a Response from the InputStream.
	 * 
	 * @return ByteArray that contains the Response
	 */
	public ByteArray readResponse() throws IOException {
		return readResponse(null);
	}

	/**
	 * Read a Response from the InputStream.
	 * 
	 * @return ByteArray that contains the Response
	 */
	public ByteArray readResponse(ByteArray ba) throws IOException {
		if (ba == null)
			ba = new ByteArray(new byte[128], 0, 128);

		byte[] buffer = ba.getBytes();
		int idx = 0;
		for (;;) { // read until CRLF with no preceeding literal
			// XXX - b needs to be an int, to handle bytes with value 0xff
			int b = 0;
			boolean gotCRLF = false;

			// Read a CRLF terminated line from the InputStream
			while (!gotCRLF && ((b = bin.read()) != -1)) {
				switch (b) {
				case '\n':
					if ((idx > 0) && buffer[idx - 1] == '\r')
						gotCRLF = true;
				default:
					if (idx >= buffer.length) {
						int incr = buffer.length;
						if (incr > maxIncrement)
							incr = maxIncrement;
						ba.grow(incr);
						buffer = ba.getBytes();
					}
					buffer[idx++] = (byte) b;
				}
			}

			if (b == -1)
				throw new IOException("Connection dropped by server?");

			// Now lets check for literals : {<digits>}CRLF
			// Note: index needs to >= 5 for the above sequence to occur
			if (idx < 5 || buffer[idx - 3] != '}')
				break;

			int i;
			// look for left curly
			for (i = idx - 4; i >= 0; i--)
				if (buffer[i] == '{')
					break;

			if (i < 0) // Nope, not a literal ?
				break;

			int count = 0;
			// OK, handle the literal ..
			try {
				count = ASCIIUtility.parseInt(buffer, i + 1, idx - 3);
			} catch (NumberFormatException e) {
				break;
			}

			// Now read 'count' bytes. (Note: count could be 0)
			if (count > 0) {
				int avail = buffer.length - idx; // available space in buffer
				if (count + incrementSlop > avail) {
					// need count-avail more bytes
					ba.grow(minIncrement > count + incrementSlop - avail ? minIncrement
							: count + incrementSlop - avail);
					buffer = ba.getBytes();
				}

				/*
				 * read() might not return all the bytes in one shot, so call
				 * repeatedly till we are done
				 */
				if (listener != null) {
					listener.start();
				}
				int actual;
				while (count > 0) {
					actual = bin.read(buffer, idx, count);
					if (listener != null) {
						listener.read(actual);
					}
					count -= actual;
					idx += actual;
				}
				if (listener != null) {
					listener.end();
				}
			}
			// back to top of loop to read until CRLF
		}
		ba.setCount(idx);
		
		return ba;
	}

}
